Heretofore, there have been known scroll compressors including, in a housing, a fixed scroll having a fixed plate and a spiral fixed lap upstanding on the fixed plate and a movable scroll having a movable plate and a spiral movable lap upstanding on the movable plate, the fixed and movable laps interleaving each other. The movable scroll is caused to orbit by an eccentric drive pin for moving a compression chamber, which is defined by the laps of the fixed and movable scrolls, the fixed plate, and the movable plate, progressively from an outer circumferential region toward a central region to compress a fluid in the compression chamber.
In one such scroll compressor disclosed in Japanese Laid-Open Patent Publication No. 11-082335, a movable scroll and a fixed scroll are disposed in a front housing, and the fixed scroll is fixed to a rear housing connected to an end of the front housing. A refrigerant that is compressed by the movable scroll and the fixed scroll is introduced through an inlet hole defined in the rear housing into a separation chamber having a separation pipe. Thereafter, the refrigerant and a lubricating oil contained in the refrigerant are separated from each other, and the lubricating oil is discharged through a discharge hole into an oil storage chamber. The fixed scroll has an oil supply hole defined therein which extends from a fixed side plate thereof toward a fixed spiral member. The lubricating oil in the oil storage chamber flows out of the oil supply hole to lubricate the vicinity of sliding portions of the movable and fixed scrolls.
According to the above conventional art, the oil supply hole defined in the fixed scroll is elongate along the axial direction of the fixed scroll and extends through the fixed scroll so as to face the sliding portion of the movable plate of the movable scroll. However, since the oil supply hole is elongate, the efficiency with which to machine the oil supply hole is low.
The oil supply hole that is supplied with the lubricating oil is of a small diameter and has an opening facing a sliding portion of the movable plate of the movable scroll. Therefore, dust or the like enters the oil supply hole from the sliding portion, tending to produce a clogging for the lubricating oil and fail to provide sufficient lubrication.
In order to prevent such a clogging in the oil supply hole, the compressor has a counterbore defined in the opening of the oil supply hole, the counterbore having a diameter larger than the oil supply hole. However, the process of additionally machining the counterbore increases the time required to manufacture the compressor.